Apparatus for forming twisted pairs of conductor wire

ABSTRACT

Apparatus for forming twisted pairs of electrical conductor wire cut to predetermined lengths and having one wire end of a pair longitudinally offset from the adjacent end of the other wire of the pair. The apparatus includes plural wire preparation units which operate to cut predetermined lengths of wire and strip insulation from one or both ends of each wire. The wire preparation units are operable to feed prepared wires to a rotary wire carrier which includes a plurality of pairs of side by side elongated wire receiving tubes. The wire carrier is rotatably indexable from a wire receiving position to a position where a wire offsetting device comprising a fluid operated clamp and linear actuator operates to longitudinally offset one wire of a pair of wires prior to a twisting operation. The wire carrier is further indexable to a position wherein a pair of wires becomes engaged with a wire tensioning device and the adjacent ends of a pair of wires are gripped by a twisting and pulling apparatus. The twisting and pulling apparatus includes a linearly movable carriage having a pair of rotatable gripping jaws which grip adjacent ends of a pair of wires and withdraw the wires from the wire carrier tubes through the tensioning device while rotating. The combined linear and rotary movement of the gripping jaws is controlled to impart a predetermined number of twists to a wire pair.

United; States atent n91 Loy et al.

[ Ange, 11974 APPARATUS FOR FORMING TWISTED PAIRS OF CONDUCTOR WIRE [75] Inventors: Fred W. Loy, Whitehall; William J.

Harms, Nunica; Charles W. Wojahn, Holland; Frederick Karasinski, Grand Rapids, all of Mich.

[731 Assignee: Gardner-Denver Company, Quincy,

Ill.

[22] Filed: Mar. 20, 1972 [21] App]. No.: 236,413

[52] US. Cl. 140/149, 57/34 R [51] Int. Cl B21f 7/00 [58 Field of Search 57/1 R, 34 R, 156; 140/149, 1; 81/951 [56] References Cited UNITED STATES PATENTS 1,336,159 4/1920 Rice 140/149 2,835,283 5/1958 Thone et al 140/149 3,052,081 9/1962 Wallshein 57/156 X 3,254,923 6/1966 Marks et a1... 140/149 X 3,309,948 3/1967 Falken 81/951 3,380,487 4/1968 Kruszeski et a1 140/149 3,526,034 9/1970 Beurricr 57/156 X 3,553,813 1/1971 Brown, Jr. ct a1. 81/951 X 3,616,531 11/1971 Tyler 140/149X 3,706,329 12/1972 Schofield 140/149 3,750,720 8/1973 Steigerwuld 140/149 Primary lQcamine rJohn Wjluekert Assistant Examiner-Charles Gorenstein Attorney, Agent, or FirmM. E. Martin 57 ABSTRACT Apparatus for forming twisted pairs of electrical conductor wire cut to predetermined lengths and having one wire end of a pair longitudinally offset from the adjacent end of the other wire of the pair. The apparatus includes plural wire preparation units which operate to cut predetermined lengths of wire and strip insulation from one or both ends of each wire. The wire preparation units are operable to feed prepared wires to a rotary wire carrier which includes a plurality of pairs of side by side elongated wire receiving tubes. The wire carrier is rotatably indexable from a wire receiving position to a position where a wire offsetting device comprising a fluid operated clamp and linear actuator operates to longitudinally offset one wire of a pair of wires prior to a twisting operation. The wire carrier is further indexable to a position wherein a pair of wires becomes engaged with a wire tensioning device and the adjacent ends of a pair of wires are gripped by a twisting and pulling apparatus. The twisting and pulling apparatus includes a linearly movable carriage having a pair of rotatable gripping jaws which grip adjacent ends of a pair of wires and withdraw the wires from the wire carrier tubes through the tensioning device while rotating. The combined linear and rotary movement of the gripping jaws is controlled to impart a predetermined number of twists to a wire pair.

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START 7 OFFSET v 7 444 4 50 45/ 446 OFFSET CONTROL 453 OFFSET CONTROL U 455 457 OFFSET j COMPLETE APPARATUS FOR FORMING TWISTED PAIRS OF CONDUCTOR WIRE BACKGROUND OF THE INVENTION It is known in the art of electrical circuitry design that the placement of signal carrying conductors in close proximity to one another often causes certain signal interference problems. Such signal interference is due to the electromagnetic field generated by the signal carried by one conductor inducing an unwanted signal in a closely adjacent conductor in accordance with known physical principles. Such signal interference, sometimes known as crosstalk, is particularly troublesome in designing circuitry for electronic communications and data processing equipment. A desired way of eliminating the aforementioned type of signal interference is to design circuits wherein the conductors are arranged as pairs of wires twisted one around the other, one wire being the signal carrying wire and the other wire being the circuit completing or ground wire.

In electronic circuits using conductor wires connected to terminals by wrapping the wire end in a series of helical convolutions on the terminal, or by using mechanical connectors it is necessary to prepare pairs of twisted wires having insulation removed from the end portions. I-Ieretofore, twisted wire pairs or other twisted multiple wire conductors have been prepared by manually cutting and stripping insulation from pretwisted pairs of wires or from twisted pairs supplied in one continuous bulk quantity. Such manual preparation of wire pairs for complicated electrical circuits is costly and undesirably slow. Moreover, the correct length of wire and the correct length of the stripped portion of the wire is difficult to achieve consistently with manual operations.

It is also a problem in the preparation of twisted pairs of conductor wires to rapidly and accurately provide precut lengths of twisted pairs wherein one wire end is offset longitudinally with respect to the adjacent end of the other wire of a pair. Longitudinal offset is required in many circuits due to the location of the respective terminals to which the individual wires of a twisted pair are to be'connected and due to the routing of the wire on the terminal board. The use of twisted pairs of conductor wires in increasing quantities for assembling electrical circuits has presented a need for apparatus which can rapidly and accurately prepare quantities of twisted multiple conductor wires cut to predetermined lengths with insulation removed from the wire ends, and with adjacent ends offset longitudinally one from another.

SUMMARY OF THE INVENTION The present invention provides apparatus for forming twisted multiple conductor wires of predetermined length, and having a predetermined length of insulation cut and stripped from the respective wire end portion, if desired. The apparatus of the present invention includes a plurality of wire cutting and insulation stripping units which can be controlled to cut predetermined lengths of wire and to strip predetermined lengths of insulation from the ends of said lengths of wire. The apparatus of the present invention als includes a wire carrier which is operable to receive also wires cut by the cutting and stripping units and transport pairs of cut wire lengths to a wire twisting apparatus wherein a pair of twisted conductor wires may be formed having a predetermined number of twists per unit length and having a predetermined twisted length.

The apparatus of the present invention further includes means for longitudinally offsetting the ends of one wire of a pair of wires with respect to the other wire of the pair. Accordingly, with the apparatus of the present invention pairs of twisted wires may be prepared with or without insulation stripped from the respective wire ends. The twisted pairs of wires may be formed to be of equal length with or without longitudinal offset of the wire ends. The twisted pair of wires may also be prepared to be of unequal length with longitudinal offset at one end of the pair, or with equal or unequal offset at both ends of the pair.

Further, according to the present invention apparatus is provided which is operable to twist a pair of conductor wires one about the other in a predetermined number of twists and in a predetermined number of twists per unit length. With the apparatus of the present invention the number of twists per unit length of wire may be varied in accordance with the requirements for certain wire diameters and types of insulation so as to prevent unwanted detwisting during circuit assembly operations.

The present invention also provides apparatus which may be controlled to form twisted pairs of wires in a substantial range of wire length and with variable amounts of wire end offset; Moreover, the present invention provides an improved method of preparing twisted pairs of conductor wire which is faster and produces more accurately formed pairs of wire than theretofore known processes.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal elevation of an apparatus for forming twisted pairs of conductor wires according to the present invention;

FIG. 2 is a plan view of a portion of an electrical terminal board with a twisted pair of conductor wires attached thereto;

FIG. 3 is a transverse elevation taken along the line 3-3 of FIG. 1;

FIG. 4 is a transverse elevation taken along the line 4-4 of FIG. 1;

FIG. 5 is a longitudinal elevation of one of the wire cutting and stripping units;

FIG. 6 is a view taken along the line 6-6 of FIG. 5;

substantially FIG. 7 is a longitudinal section view through one of the wire carrier tubes and its associated wire retaining clamp;

FIG. 8 is a fragmentary end view of the wire carrier means showing two adjacent wire retaining clamps;

FIG. 9 is a section view taken along the line 9-9 of FIG. 1 showing the wire carrier tube extending mechamsm;

FIG. 10 is a section view taken along the line 10-10 of FIG. 9;

FIG. 11 is a plan view of the wire offsetting actuator taken along the line Ill-I1 of FIG. 3;

FIG. 12 is a fragmentary elevation taken in the same direction as FIG. 1 showing the wire tensioning device and a portion of the wire twisting and pulling apparatus;

of FIG. 13;

' FIG. 15 is a detail view on a larger scale of a portion of FIG. 13;

FIG. 16 is a detail view on a larger scale of a portion of FIG. 14;

FIG. 17 is an offset section view taken substantially along the line 17--17 of FIG. 18 to show how the components of the wire twisting apparatus are interengaged;

FIG. 18 is an end view of the wire twisting apparatus taken from the line 18-18 of FIG. 1;

FIG. 19 is a detail view of the wire twisting jaws; and,

FIGS. 20 through 22 are schematic diagrams of a control circuit for the apparatus of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 of the drawings an apparatus for forming twisted pairs of conductor wires is shown and generally designated by the numeral 10. The apparatus 10 comprises an elongated base 12 having mounted thereon a pair of spaced apart upstanding support members 14 and 16, see FIG. 3 also. Mounted on the support members 14 and 16 are two conductor wire cutting and insulation stripping units generally designated by the numerals 18 and 20. The units 18 and 20 will be referred to hereinafter as the wire strippers 18 and 20. Each wire stripper is adapted to receive insulated conductor wire from the respective bulk reels 22 and 24, suitably mounted on the base 12, and to supply predetermined lengths of wire with predetermined lengths of insulation stripped from each end. The wire strippers shown in use as part of the apparatus 10 are of a known type and are essentially the same in construction and operation as a machine which is commercially available from the assignee company of the present invention and designated as the Model 14YA Wire Preparation Unit. Similar types of wire strippers which could be adapted to be used with the apparatus 10 are disclosed in US. Pat. Nos. 2,884,825;3,l03,735; and 3,6l2,l l l. A general description only of the wire strippers 18 and 20 will be made herein to facilitate understanding of how they work in conjunction with the apparatus 10.

Referring to FIG. 5 and 6 the stripper 20 includes a frame 26 having a longitudinal slot 28 formed on the lower side. A slide member 30 mounted in the slot 28 and suitably retained therein supports a wire feed mechanism 32 comprising an electrical rotary stepping motor 34 having a shaft 36. The stepping motor 34 is of a known type, commercially available, which is responsive to rotate a predetermined amount when energized by an electrical signal and is precisely braked when deenergized to give positive rotary position control of the shaft 36. Attached to the shaft 36 is a combination feed .wheel and gear 38, the gear portion of which is engaged with an adjacent combination feed wheel and gear 40. The feed wheel 40 is rotatably mounted on a pivoted support 42. Insulated conductor wire 44 is trained through a guide 46 and between the wheels 38 and 40 which grip the wire and, in response to operation of the stepping motor 34 feed the wire to the right viewing FIG. 5. The wire 44 passes through a fluid operated releasable clamp 48 mounted on the slide 30 and through a guide tube 50 to a wire cutting blade assembly 52 and insulation cutting blade assemblies 54 and 56. The wire 44 then passes through a passage 57 in a second fluid operated releasable clamp 58.

The wire and insulation cutting blade assemblies are similar in construction with the exception that the insulation cutting blades out only through the insulation and not the conductor wire. The blade assemblies 52, 54 and 56 are slidably mounted in suitable slots in a blade support frames 60. FIG. 6 illustrates the arrangement of the insulation cutting blade assembly 54 which is typical of all three of the blade assemblies. The blade assembly 54 includes a pair of opposed cutting blades 62 and 64 each connected to an elongated pin 66. The pins 66 are connected to pairs of arms 68 which are pivotally mounted on the frame 26 at 71). The arms are also connected to a fluid operated linear actuator '72. As shown in FIG. 5 two actuators 72 and sets of arms are provided for actuating the blades. In response to pressure fluid being supplied to the actuators 72 from a suitable source through control means, not shown, the blade assemblies 52, 54 and 56 may be simultaneously closed and opened at will.

Referring again to FIG. 5 the slide member 30 includes a projection 74 which is connected to a pressure fluid linear actuator 76. The releasable clamp 58 also includes a projection 78 which is connected to another pressure fluid linear actuator 80. The operation of the stripper unit is generally as follows. A predetermined length of wire is fed through the stripper 20 by energizing the stepping motor 34 with a pulse type electrical signal to cause the motor to rotate a predetermined amount which corresponds to a predetermined equivalent linear translation of the periphery of the feed wheel 38 and 40 which are always engaged with the wire 44. When the desired length of wire has been fed past the blade assembly 52 the releasable clamps 48 and 58 are actuated to clamp the wire 44. The actuators 72 are also energized to close the blade assemblies 52, 54 and 56 cutting the wire and cutting the insulation at a predetermined point on either side of the wire cut. With the blade assemblies closed the actuators 76 and 80 are energized to respectively move the slide member 30 and releasable clamp 48 to the left, viewing FIG. 5, and the releasable clamp 58 to the right. This motion operates to strip the insulation from the trailing end of the wire portion that has been fed past the blade assembly 52 and to strip the insulation from the leading end of the wire portion which is still uncut from the bulk reel 24. After the actuators 76 and 80 have moved to perform the insulation stripping operation, the clamps 48 and 58 are released and the actuators 76 and 80 are energized to move in the opposite direction back to the positions shown in FIG. 5. The uncut wire portion, positively gripped by the feed wheels 38 and 40, moves with the slide member 30 back to the position of FIG. 5 ready for a succeeding cycle of feeding and cutting. The wire that has been cut and now had insulation stripped from both ends had been fed into wire carrier means on the apparatus 10 which will now be described in detail.

WIRE CARRIER AND INDEXING DEVICE Referring to FIGS. 1,3"and 4 the apparatus 10 ineludes wire carrier means generally designated by the numeral 82. The wire carrier 82 includes an elongated shaft 84 rotatably supported at one end in a bearing support 86, which is mounted on a member 87, and at the opposite end in a support member 88 attached to the wire stripper 20, see FIGS. 3 and 12. The wire carrier 82. further includes circular plates 90, 92 and 94 spaced along and attached to the shaft 84. The plates 90, 92, and 94 comprise support members for four pairs of elongated tubes 96 and 98. Each tube 96 is mounted closely adjacent and parallel to a tube 98 to form the pairs. The tubes 96 and 98 comprise means for receiving and supporting pairs of conductor wires cut to predetermined lengths. The tubes 96 and 98 pass through suitable openings in the support plates and each pair of tubes is spaced at ninety degree intervals around the periphery of the plates. A bracket 99, one

shown in FIG. 4, is clamped to each tube 96 and 98 and the opposite tube of each pair passes through a suitable opening in the bracket. The brackets 99 prevent rotation of the tubes 96 and 98. The tubes are longitudinally movable with respect to the plates for a purpose to be explained herein.

Referring to FIGS. 7 and 8, the ends of the tubes 96 and 98 adjacent the plate 90 are each fitted with a re leasable wire retaining clamp 100. The retaining clamps 100 each comprise a member 102 fastened to the tube and including an opening 104 aligned with the end of the tube. The member 102 includes a transverse bore 106 in which a plunger 108 is disposed and biased by a spring 110 to clamp a wire 112 as shown in FIG. 7. The plunger 108 includes an opening forming a wire clamping surface 114. The plunger 108 also includes a head portion 116 which is engageable to move the plunger to release the clamping force on the wire 112 and to permit insertion or removal of a wire with respect to the tube 96. The plunger 108 also includes a stem 118 projecting from the member 102.

Referring to FIGS. 1 and the wire carrier shaft 84 extends through the bearing support 86 and is drivably connected to the shaft 120 of a fluid operated rotary indexing device 122. The indexing device 122 is a generally well known type, similar to a device disclosed in U.S. Pat. No. 3,103,735, and characterized by a pressure fluid piston and cylinder 124, FIG. 9, wherein a piston rod is connected to a gear rack, not shown, which in turn is engaged with a gear for converting linear motion to rotary motion. Suitable mechanism is provided for positively limiting the rotary motion for each operating cycle of the cylinder actuator. The indexing device 122 is disposed to rotate or index the shaft 84 and wire carrier 82 ninety degrees each time the cylinder 124 is energized. Although other types of indexing devices may be used in place of the indexing device 122, a suitable device, commercially available, is a model 725 indexing table manufactured by the Allenair Corp., Mineola, New York, USA.

The indexing device 122 includes limit switches 126, FIG. 9, and 128, FIG. 1, which are actuated by suitable mechanism to indicate, respectively, that the device 122 is ready to perform an indexing operation and that an indexing operation has been completed.

As previously mentioned, the tubes 96 and 98 are longitudinally movable with respect to the shaft 84 and plates'90, 92 and 94. The purpose of moving the tubes is to place the end of each tube having the wire retaining clamp 100 closely adjacent the releasable clamps 58 of the wire strippers 18 and 20 so that a predetermined length of wire may be fed from each stripper into a tube. An extended position of a tube 96 for receiving a wire from the wire stripper 20 is shown by the dashed lines in FIG. 12. Referring to FIGS. 9 and 10 the bearing support 86 has fastened thereto a circular plate 130 having a circumferential groove 132. Each of the tubes 96 and 98 includes a rectangular block 134 fastened thereto and disposed partly in the groove 132. Mounted on the plate 130, approximately apart, are pressure fluid cylinder and piston type actuators 136 and 138 each having a head 140 attached to the end of a piston rod. The heads 140 are movable through openings 142 in the plate and have circumferential grooves 144 formed to be aligned with the groove 132 in the plate 130 as shown in FIG. 10. Each time the wire carrier 82 is indexed by the indexing device 122 a block 134 of tubes 96 and 98 of two adjacent pairs of tubes are aligned with the openings 142 and are disposed in the groove 144 of the heads of the respective actuators 138 and 136. Referring to the direction of rotation of the wire carrier 82 indicated by the arrow 146 in FIG. 9 the tube 96 of one pair of tubes is in position to be extended by the actuator 138 and is also aligned with the opening 57 in the releasable clamp 58 of the wire stripper 20. The tube 98 of the preceding adjacent pair of tubes is in position to be extended by actuator 136 and is aligned with the releasable clamp 58 of the wire stripper 18. Accordingly, when the actuators 138 and 136 are energized to extend the heads 140 to the position shown by the dashed lines in FIG. 10 tubes 96 and 98 of adjacent pairs are extended to receive a wire fed by the wire strippers 20 and 18, respectively. The heads 140 are each engageable with limit switches 148 when in the retracted position shown in FIG. 10, and when they move from the retracted to the extended position switches 150 are engaged to close. The pairs of switches 148 and 150 are part of a control circuit for the apparatus 10 to be explained further herein. When the actuators 138 and 136 extend the tubes 96 and 98 to receive a wire from the wire strippers 20 and 18 they are deenergized to allow for some retraction movement of the tubes when the releasable clamps 58 on the wire strippers are moved to strip the insulation from the trailing end of the wires being loaded into the tubes. The actuators are later energized to retract the tubes to the indexing position.

When the tubes 96 and 98 are extended into position for receiving wires from the wire strippers the respective wire retaining clamps 100 must be opened to provide for insertion of wires into the tubes. Referring to FIG. 3 the frame 26 of the wire stripper 20 has attached thereto a bracket 1S2. Mounted on the bracket 152 is a pressure fluid cylinder 154 having a piston rod 156 with a member 158 attached to its distal end. The member 158 is also engaged with a guide bar 160 attached to the bracket 152. When a tube 96 is extended to receive a wire from the releasable clamp 58 of the wire stripper 20 the plunger 108 of a wire retaining clamp 100 is in position to be engaged by the member 158. Prior to feeding a wire into tube 96 the actuator 154 is energized to move the plunger 108 to open the clamp. When a wire is received in the tube 96 and properly prepared by the wire stripper 20 the actuator 154 is deenergized and becomes operable to retract the member 158 so that the clamp 100 retains a wire within the tube. A similar actuator 162, having a piston rod 164,

is mounted on the wire stripper 18 and is controlled to open a wire retaining clamp 100 of a tube 98 when the latter is extended to receive a wire. A wire detector switch 163 mounted on the stripper 18 is disposed to be actuated by the end portion of a wire projecting from a tube 96 when the wire carrier 82 is indexed.

Similarly a switch 165 mounted on a support 194 is po sitioned to be actuated by a wire disposed in a tube 98.

WIRE OFFSET ACTUATOR The apparatus further includes means for longitudinally offsetting the end of one wire of a pair with respect to the other wire prior to the twisting operation. Since the wire strippers 18 and may be controlled to provide wires of different lengths a pair of twisted wires may be prepared which are longitudinally offset at one end without performing an offsetting operation. However, in many applications of twisted pairs of conductor wires equal wire lengths with equal amounts of longitudinal offset are required as well as unequal wire lengths with unequal amounts of offset. FIG. 2 shows a typical application of a pair of twisted conductor wires 166 connected to spaced apart terminals 168 on a terminal board 170. Although it is desirable to maintain the wires twisted throughout as much of their length as possible the required terminal connection pattern and wire routing makes necessary the greater length of wire 172 beyond the final twist. Hence the ends of the wires of the pair 166 are longitudinally displaced or offset one from the other a desired amount prior to twisting.

Referring to FIGS. 3 and 11 the offsetting means is characterized by a reversible fluid operated cylinder and piston actuator 174 mounted on the support 16 and in a housing 176 which in turn is mounted on the support 14. The actuator 174 includes fluid inlet conduits 173 and 175 which are connected to a suitable valve, not shown, to provide reversible movement of a piston rod 177. The piston rod 177 has a portion 178 extending from one end of the actuator 174 and a portion 180 extending from the opposite end. Attached to the distal end of the rod portion 178 is a bracket 182 having a U-shaped portion 184. A small fluid operated actuator 186 is mounted on the bracket portion 184 and includes a movable clamping jaw 188 attached to its piston rod. The bracket 182 is slidably supported on a guide bar 190 suitably mounted on the support 176. As shown in FIGS. 3 and 11 the cylinder actuator 174 is positioned on the apparatus 10 such that when the wire carrier means 82 is indexed to receive wires in tubes 96 and 98 of adjacent pairs of tubes a tube 96 of may be partially withdrawn from a tube 96 during the offset operation. Also mounted on the support 194 is a fluid operated linear actuator 200 having a knifelike guide plate 202 attached to its piston rod. When a wire in a tube 96 is clamped for the offsetting operation the actuator 200 is also energized to position the guide plate 202 between the tubes 96 and 98 to positively separate the wires extending from the retaining clamps and prevent accidental clamping and offset of the wire in a tube 98.

The amount of longitudinal offset of the wire in a tube 96 is controlled by means comprising a movable abutment 204 engageable with the end of the piston rod portion 180. The abutment 204 comprises an elongated rod having a threaded portion 206 engaged with threads formed in a housing 208. A suitable crank 210 is connected to one end of the rod 204 and a lockscrew 212 is disposed on the housing 208 and engageable with the rod. An elongated opening 214 in the housing 208 is provided with suitable indicia 216 for indicating the amount of offset by aligning a collar 218 fixed on the rod 204 with the desired numbered setting. Accordingly, a predetermined amount of longitudinal offset including no offset movement may be provided for a wire in a tube 96 by positioning the end of the abutment rod 204 to be engaged by the piston rod portion when the actuator 174 is energized to move downwardly, viewing FIG. 11.

WIRE TENSIONING DEVICE The apparatus 10 also includes means for withdrawing a pair of wires which are located in tubes 96 and 98 of a pair of tubes and twisting one wire about the other to form a twisted configuration generally like that shown by the example of the twisted pair 166 of FIG. 2. After the wire carrier means 82 has been rotatably indexed to place a pair of tubes 96 and 98 adjacent the offsetting actuator 174 the indexing device 122 is further actuated to index the wire carrier to place a pair of wires in wire tensioning means characterized by a device shown in FIGS. 12 through 16 and generally designated by the numeral 220. The wire tensioning device 220 includes a housing 222 mounted on a bracket 223 which in turn is adjustably fastened to the base 12. The housing 222 includes a recess 224 in which is disposed a'movable wire guide plate 226. The wire guide plate is characterized by sloping surfaces 228 and 230 which converge to a vertical slot 232 as shown in FIGS. 13 and 15. The guide plate 226 is retained in the recess 224 by a cover plate 234 shown removed in FIG. 13. The housing 222 also includes a bore 236 in which is disposed a cylindrical pin 238 having a conical end portion 240. The end of the pin 238 opposite the conical portion 240 is connected to a member 242 which in turn is connected to the end of a piston rod 244 of a pressure fluid cylinder actuator 246. The actuator 246 is mounted on a downwardly projecting portion 248 of the housing 222. The pin 238 and guide plate 236 are connected to move together by a pin 250 movable in a slot 252 in the housing 222 as shown in FlG. 13.

The housing 222 includes a transverse slot 254 having a somewhat V-shaped opening 256 to the side of the housing. The slot 254 is operable to receive the end portions of a pair of wires 258 and 260 extending from the wire retaining clamps 100 as a pair of tubes 96 and 98 are indexed into a position ninety degrees displaced from the wire offsetting actuator 174. As shown in FIG. 15 the cover plate 234 includes an opening formed partly by the sloping surface 255 which intersects a transverse slot 257. The slot 257 is slightly smaller in width than the slot 254. When a pair of wires 258 and 260 are in the position shown by the dashed lines in FIG. 15 the actuator 246 is energized to move the pin 238 and guide plate 226 from a downward or retracted position, not shown, to the position shown in FIG. 13. As the pin 238 and plate 226 are moved upwardly, viewing FIGS. 13 and 15, the pin 238 moves between the wires 258 and 260 while the wire 260 is engaged by the surface 228 and wire 258 is engaged by surface 230 on the guide plate. The resultant action is movement of wire 258 into the slot 232 in a position over the wire 260 as shown in FIG. 15 and bending of the wires par tially around the pin 238 as shown in FIG. 14. The slot 232 in the guide plate 226 is formed to have radii 262, FIG. 16, between the sides of the slot and the inner face 264. The size of the radii 262 as well as the width of the slot 232 and the position of the plate 226 with respect to the pin 238 have been determined to have an effect on the magnitude of the force which resists movement of the wires 258 and 260 around the pin and through the slot 232 as they are longitudinally withdrawn from the tubes 96 and 98. It has been determined that different wire diameters and types of insulation require different magnitudes of frictional drag on the wires as they are pulled through the tensioning device 220. Accordingly, the size and shape of the radii 262 may be changed to provide the desired amount of force required to pull the wires through the device. Moreover, the diameter of the pin 238 and the position of plate 226 with respect to the pin may also be varied to con trol the tension in the wires as they are withdrawn.

As shown in FIG. 12 the tensioning device 220 includes a fluid operated cylinder type actuator 226 having a member 268 which engages the plungers 108 to open the wire retaining clamps 100 to allow wires to be pulled from a pair of tubes 96 and 98. The stems 118,

' one shown, of the retaining clamp plungers 108 engage an actuating member 270 of an electrical switch 272 to hold the switch open as long as a wire is disposed in either tube of a pair of tubes 96 and 98. The wire tensioning device 220 also includes an electrical switch 274 positioned to be actuated by the member 242 when the actuator 246 moves the plate 226 and pin 238 to the position shown in FIG. 13.

WIRE TWISTING APPARATUS Referring to FIGS. 1, l7 and 18 the apparatus 10 is further characterized by a movable apparatus, generally designated by the numeral 276, comprising means for twisting a pair of wires together while withdrawing the wires from the wire carrier 82 and through the wire tensioning device 220. The wire twisting apparatus 276 includes a carriage 278 which is slidably mounted on two cylindrical rods 280 which are mounted on supports 282 and 284 on the base 12 and substantially parallel to the shaft 84. An elongated screw 286 having a helical groove formed thereon is also mounted between the supports 282 and 284 and is nonrotatably secured to the supports. The screw 286 is part of a well known type of actuator commonly known as a ball bearing screw. Referring to FIGS. 17 and 18 the screw 286 cooperates with a nut 288 which contains a plurality of ball bearings which circulate in a closed pathway between the helical groove on the screw 286 and the nut. The ball bearing screw and nut is a well known device for converting rotary motion to linear motion. The nut 288 and screw 286 comprise drive means for linearly moving the carriage 278 toward and away from the wire carrier 82. The nut 288 is mounted on a cylindrical hub 290 which is supported in a flanged portion 292 of a hollow shaft 294. The shaft 294 is rotatably mounted in suitable bearings 296 disposed in the carriage 278 and is secured in the bearings by a nut 298. The hub 290 is clamped between the flanged portion 292 and a gear 300 mounted on the exterior of the hub. The hub 290, ball bearing nut 288, gear 300, and shaft 294 are operable to rotate together.

The carriage 278 also includes a rotatable shaft 302 mounted in bearings 304, disposed in the carriage. The shaft 302 includes a gear 306 which is secured to the shaft by a key 308. The shaft 302 further includes a portion 310 which is fitted in and keyed to a hub 312. A second hub 314 having a gear 316 mounted thereon is also fitted over the shaft 310 but is operable to rotate relative to the shaft. The hubs 312 and 314 are part of a device known as an electromagnetic combination clutch and brake, generally designated by numeral 318. The clutch 318 is of a type generally well known and is characterized by a housing 320 containing suitable electromagnetic windings or coils which can be selectively energized and deenergized by suitable controls, not shown. The clutch 318 is of a type which can be energized to cause the hubs 312 and 314 to rotate together, and accordingly, rotate with the shaft 302, or the hub 312 and shaft 302 can be selectively braked to stop rotating while the hub 314 is permitted to rotate with respect to the shaft 302. The above type of combination clutch and brake is commercially available and a suitable device is a model UCB-26C combination clutch and brake manufactured by the Electroid Corporation, Union, New Jersey, U.S.A. For purposes of the following description it will be assumed that when the clutch is engaged the hubs are operable to rotate together and when the clutch is disengaged the hub 312 is braked and the hub 314 is rotatable on the shaft portion 310.

The carriage 278 further includes a pneumatic rotary motor 322 having a rotary shaft 324 which includes a pinion gear 326 integrally formed thereon. The motor 322 may suitably be of the well known rotary vane type and is provided with ports 328 and 330 which can operate as either exhaust or inlet ports to provide for reversible operation of the motor. The ports 328 and 330 are respectively connected to solenoid operated valves 332 and 334 which are also connected to a source of pressure air, not shown, by a conduit 336. The valves 332 and 334 are operable to be selectively energized to provide for reversible operation of the motor 322 as will be discussed in greater detail herein. As shown in FIGS. 17 and 18 the pinion 326 is engaged with the gear 316. Referring to FIG. 18, the gear 306 mounted on shaft 302 is constantly engaged with gear 300. The gears 300 and 302 are not shown engaged in FIG. 17 because the plane of the section view does not pass directly between the centerlines of the gears 300 and 306.

The gear 316 is also engaged with a gear 338 of a pair of gears 340 rotatably mounted side by side on a shaft 342 which is removably mounted in a bore 344 in the carriage-278. The gear 338 is suitably fastened to a gear 346 to provide the pair of gears 340 which rotate together. The shaft 342 may be moved from the bore 344 to one of a number of alternate parallel bores, not shown, which are in proximity to the bore 344, and the pair of gears 340 may be interchanged with other pairs of gears of different diameters and numbers of teeth for a purpose to be explained herein.

The carriage 278 includes means for gripping and rotatably twisting a pair of wires such as the wires 258 

1. Apparatus for forming twisted pairs of conductor wire comprising: wire carrier means movably mounted on said apparatus and including wire receiving means for receiving and supporting at least two conductor wires to form a pair of wires; wire twisting means including wire gripping means for gripping the end portions of a pair of wires disposed in said wire carrier means and twisting said pair of wires together, and being disposed on said apparatus for relative longitudinal movement with respect to said wire carrier means for withdrawing said pair of wires from said wire receiving means while twisting said pair of wires together; indexing means for moving said wire carrier means from a wire receiving position to a position in which said pair of wires is gripped by said wire twisting means; and, wire tensioning means engageable with said pair of wires disposed in said wire carrier means for tensioning said pair of wires while said pair of wires is being withdrawn from said wire receiving means.
 2. The invention set forth in claim 1 wherein: said wire tensioning means comprises a housing disposed adjacent said wire carrier means and including a slot for receiving a portion of a pair of wires when said wire carrier means is moved by said indexing means.
 3. The invention set forth in claim 2 wherein: said wire tensioning means includes a cylindrical pin disposed in said housing for movement to a position between said wires of a pair of wires and said wire tensioning means includes guide means having a slot formed therein for guiding said wires to be bent at least partially around said pin while said pair of wires is being withdrawn from said wire receiving means.
 4. Apparatus for forming twisted pairs of conductor wire comprising: wire carrier means movably mounted on said apparatus and including a shaft, wire receiving means comprising elongated tube means for receiving and supporting at least two conductor wires to form a pair of wires, and support means for said elongated tube means mounted for rotation about the longitudinal axis of said shaft; wire twisting means including wire gripping means for gripping the end portions of a pair of wires disposed in said wire carrier means and twisting said pair of wires together, and being disposed on said apparatus for relative longitudinal movement with respect to said wire carrier means for withdrawing said pair of wires from said elongated tube means while twisting said pair of wires together; and, indexing means for moving said wire carrier means from a wire receivinG position to a position in which said pair of wires is gripped by said wire twisting means.
 5. The invention set forth in claim 4 wherein: said elongated tube means comprises plural pairs of elongated tubes each tube of a pair mounted adjacent and substantially parallel to the other tube of said pair and said plural pairs of tubes are mounted spaced apart on said support means about said axis of said shaft.
 6. The invention set forth in claim 5 wherein: said elongated tubes each include releasable wire retaining means for retaining said wires in said tubes while said wire carrier means is being moved by said indexing means.
 7. Apparatus for forming twisted pairs of conductor wire comprising: wire carrier means movably mounted on said apparatus and including wire receiving means for receiving and supporting at least two conductor wires to form a pair of wires; wire twisting means including wire gripping means for gripping the end portions of a pair of wires disposed in said wire carrier means and twisting said pair of wires together, and being disposed on said apparatus for relative longitudinal movement with respect to said wire carrier means for withdrawing said pair of wires from said wire receiving means while twisting said pair of wires together; indexing means for moving said wire carrier means from a wire receiving position to a position in which said pair of wires is gripped by said wire twisting means; and, wire offsetting means including means for gripping the end portion of one wire of a pair of wires for longitudinally displacing said one wire with respect to the other wire of said pair of wires while said pair of wires is disposed in said wire carrier means.
 8. The invention set forth in claim 7 wherein: said wire offsetting means is disposed on said apparatus adjacent one end of said wire carrier means and said indexing means is operable to move said wire carrier means to an intermediate position between said wire receiving position and said position in which said pair of wires is gripped by said wire twisting means whereby the end portion of said one wire is in position to be gripped by said wire offsetting means.
 9. The invention set forth in claim 8 wherein: said wire offsetting means comprises a pressure fluid operated linear actuator including a movable piston rod, and said means for gripping said end portion of said one wire comprises a fluid actuated clamp mounted on said piston rod.
 10. The invention set forth in claim 9 wherein: said wire offsetting means includes adjustable means for limiting the movement of said piston rod.
 11. The invention set forth in claim 9 together with: means movable in response to said wire carrier means being indexed to said intermediate position to be interposed between the end portions of a pair of wires for separating said wires one from the other.
 12. Apparatus for forming twisted pairs of conductor wire comprising: wire carrier means including wire receiving means for receiving and supporting at least two conductor wires to form a pair of wires, wire twisting means including wire gripping means for gripping the end portions of a pair of wires disposed in said wire carrier means and twisting said pair of wires together; and wire cutting means for cutting said wires to a predetermined length and feeding said wires to said wire receiving means, said wire cutting means including means for cutting and stripping insulation from the ends of said wires of predetermined length.
 13. Apparatus for forming twisted pairs of conductor wire comprising: wire carrier means including wire receiving means for receiving and supporting at least two conductor wires to form a pair of wires; and, wire twisting means including wire gripping means for gripping the end portions of a pair of wires disposed in said wire carrier means and twisting said pair of wires together; said wire twisting means including carriage means dispoSed on said apparatus and including drive means for moving said carriage means linearly toward and away from said wire carrier means, said wire gripping means being rotatably mounted on said carriage means for gripping and twisting a pair of wires together and withdrawing said pair of wires from said wire carrier means; and, said wire twisting means including motor means mounted on said carriage means and operable to be drivably connected to said drive means and to said wire gripping means for simultaneously operating said drive means to move said carriage means away from said wire carrier means and rotating said wire gripping means.
 14. The invention set forth in claim 13 wherein: said drive means comprises a ball nut rotatably mounted on said carriage and engaged with an elongated screw disposed on said apparatus and said carriage is responsive to rotation of said nut to be moved with respect to said wire carrier means.
 15. The invention set forth in claim 13 wherein: said wire twisting means includes clutch means interconnecting said motor means and said drive means and operable to be in an engaged condition to provide for driving said carriage linearly with respect to said wire carrier means and a disengaged condition whereby said wire gripping means may be rotated by said motor means without movement of said carriage with respect to said wire carrier means.
 16. The invention set forth in claim 13 wherein: said wire twisting means includes clutch means interconnecting said motor means and said wire gripping means and operable to be in an engaged condition to provide for rotating said wire gripping means and a disengaged condition whereby said drive means may be operated by said motor means to move said carriage without rotating said wire gripping means.
 17. Apparatus for forming twisted pairs of conductor wire comprising: wire carrier means movably mounted on said apparatus and including wire receiving means for receiving and supporting at least two conductor wires to form a pair of wires; wire twisting means including wire gripping means for gripping the end portions of a pair of wires disposed in said wire carrier means and twisting said pair of wires together, and being disposed on said apparatus for relative longitudinal movement with respect to said wire carrier means for withdrawing said pair of wires from said wire receiving means while twisting said pair of wires together; and, indexing means for moving said wire carrier means from a wire receiving position to a position in which said pair of wires is gripped by said wire twisting means.
 18. Apparatus for forming twisted pairs of conductor wire comprising: wire carrier means including wire receiving means comprising a plurality of pairs of elongated tubes for supporting a plurality of conductor wires of predetermined length in plural paired arrangement; and, wire twisting means including wire gripping means for gripping the end portions of a pair of wires disposed in said wire carrier means and twisting said pair of wires together.
 19. The invention set forth in claim 18 wherein: said wire twisting means is disposed on said apparatus for relative longitudinal movement with respect to said wire carrier means for withdrawing said pair of wires from said wire receiving means while twisting said pair of wires together.
 20. The invention set forth in claim 18 together with: wire cutting means for cutting said wires to a predetermined length and feeding said wires to said wire receiving means. 